This invention relates to impact-modified polyvinyl chloride (PVC) compositions. More particularly, this invention relates to high impact compositions comprising PVC and a cross-linked elastomeric polyester.
Vinyl chloride polymers, without further modification, are brittle, inflexible low-impact materials. Methods for improving the impact properties of PVC have included forming blends of PVC with a second polymeric resin such as ABS or MBS resin, or a chlorinated olefin rubber. Examples of such modifiers are disclosed in U.S. Pat. Nos. 3,264,373, 3,886,232 and 3,467,732.
Linear aliphatic polyester elastomers have long been known in the art. These polymers are generally compatable with PVC and linear, uncross-linked polyesters have been found to be useful as plasticizers for PVC, as is disclosed in U.S. Pat. No. 3,501,554. These polyester plasticizers markedly improve the flexibility and processability of PVC, but do not effect a significant improvement in impact properties.